Sound-absorbing method and material



Patented Feb. 12, 1924.

UNITED STATES 1,483,366 PATENT OFFICE.

JAG JOB mm, 01 BHILADELPHIA, PENNSYLVANIA.

sounn-ansoimmo METHOD AND MATERIAL.

Continuation-o! application Serial Ho. 242,272, filed June 27, 1918 Thisapplication filed October 9, 1922.

Serial 1T0. 598,353.

To all whom it may com-em;

Be it known that I, JACOB MAznR, a citizen of the United States, andresident of Philadelphia, in the county of Philadelphia and State ofPennsylvania, have invented a new and useful Improvement inSound-Absorbing Methods and Material;

and I do hereby declare the following to b; a full, clear, and exactdescription there- My invention relates to the art of correcting theacoustics of rooms, auditoriums and other enclosures, and its object isto provide a novel and effective method and means for modifying theboundary surfaces of such enclosures to produce definite andpredetermined sound modification.

In m" application for Letters Patent filed June 2, 1918, Serial No.242,272, I have described and claimed an improvement in thesound-modifying art consistingin providing the surface of an enclosurewith apertures communicating freely with the auditorium or otherenclosure, and so disposed as to their size, number and arrangement asto give a definite and predetermined sound-absorbing capacit per unitarea of the exposed surface. 11 my said prior application I havedescribed some of the many difierent ways in which such sound-absorbingapertures may be formed.

My present application is a continuation of this prior application andrelates specifically to the use, for sound-modifying purposes, ofapertures in the nature of grooves penetrating one or more ofthe'exposedsurfaces of the enclosure to be treated. Such grooves may be formed byscoring or otherwise forming indented lines in a wall or ceiling coatedwith plaster or other material capable of such. treatment. Or, thegrooves may be made by building up a, composite-material, for example,by laying together strips of thin material and secur- .ing the assembledstrips to a suitable backin When such composite material is'applled toawallyor ceiling the edges of the stri s or other elements form theboundary sur ace of that portion of the enclosure and present spaces orgrooves between them of greater or less width, according to thecharacter of the material used. The spaces between the laminations ofsuch composite material may be varied by placing separating elementsbetween them, and such separating elements may be of various forms, someof which will be described below.

The grooves formed in these various ways need not all be parallel witheach other, but may run in different directions in accordance withanydesign that .may be desired,

while still maintaining the definite and predetermined sound-absorbingvalue that is characteristic of my system of sound-control as set forthin this application and in my prior application mentioned above.

In the accompanying drawing Fig. 1 is a perspective view showing theembodiment of my invention in which a previously erected wall or ceilingis scored to present a grooved surface; Fig. 2 is a perspective viewshowing a modification in which kerfs or, slots are employed; Fig. 3 isa perspective view of a portion of-a sound-modifying body composed ofcorrugated sheet material; and Figs. 4 to -7, inclusive, are fragmentaryperspective views showing various methods of producing grooved surfacesthrou h the use of superposed laminations.

In Fig. 1 the numeral 2 indicates a fragment of a'wall, ceiling or floorof an enclosure having its exposed surface provided with a multitude ofclosely adjacent grooves 3. Such grooves may readily be made after theplaster, or other like material, has been placed in position and beforeit has completely hardened. It will be understood that these groovesmaybe arranged in various different ways to produce a variety ofdecorative effects, and that the grooves may be of different widths anddepths and may be spaced from each other either regularly orirregularly,the only requirement being that the grooves be sufficiently numerous tohave a substantial sound-modifying effect, and that the grooved surfaceshall have definite and predetermined sound absorbing capacity per unitof its area.

In Iig. 2 is shown a modification in which a block 5 of plaster or thelike is kerfed-or slotted, as at 6, to form longitudinal grooves. Whensuch blocks are used to produce walls or ceilings with the groovesexposed, they produce a similar effect as to the absorption of sound asthe grooved surface shown in Fig. 1.

Fig. 3 shows another modification of my invention in which thesound-absorbing material consists of units or blocks of corboard or thelike, which is bent into convolutions 8, thus presenting at the outersurface grooves or passages similar to the grooves 3 and 6 of Figs. 1and 2.- This corrugated material may be secured to a backing sheet 9 bywhich the material is held together as a unitary structure. By dippingsuch materi'al in a solution of silicate of soda or other stiffeningmedium, a rigid and effective sound-modifying material is very cheaplymade.

Fig. 4: shows-the simplest method of carrying my invention into' etl'ectby the use of superposed laminations, the edges of which form thenormally exposed surface of the material. As shown in this figure,strips 11 of paper, fiber-board, cloth, felt or the like may be laidtogether and secured to a backing member 12 by means of cement orotherwise. The edges 13 of these strips will necessarily present spacesor grooves between them of greater or less width. It the strips are madeof smooth material and are closely compacted together, the spaces orgrooves between them will be of small or even microscopic width, butwill have substantial sound-modifying power. By employing stripsoirougher material the efiective'spaces or rooves between the strips maybe increased, as desired. The exposed edges 13 may present a flat evensurface, as shown in Fig. l, or may be more or less irregular and rough,according to the desired appearance and sound absorbing capacity. I

Fig. 5 differs from Fig.4 in that the laminations 14 secured, as in Fig.4, to a backing sheet 15, are separated by means of particles 16 of feltfiber, sand or other suitable finely-divided.material which produceseffective spaces between the laminations of controllable width. Theparticles 16 may themselves be ofhigh sound-absorbing power, thusproviding an additional means for regulating the absorption of sound.

In Fig. 6 the strips or layers 17 may be positively spaced apart in auniform manner by means of spacing strips 18, thereby formingsound-absorbing apertures between the strips.

Fig. 7 shows a modification similar to that of Fig. 6 .with thedifference that the laminations 19 are spaced apart by strips or blocks20 which do not extend fully across the width of the strips 19, andwhich may be staggered in position, as illustrated, to form more 'orlessirregular openings for the absorption of sound. In this case it will benoted that the openings extending inward from the'edges of the adjacentstrips 19will communicate with cross openings, such, for example as 21,between the ends of the short spacers 20, and consequently the openingsextending inwardly from the exposed surface of the material may alsocommunicate one with the. other.

It will be understood that the foregoing examples are described merel toillustrate the many ways in which my invention may be employed, withoutlimitingmy invention to the constructions herein shown. In particular,it will be noied that the grooves which I employ may be either uniformor non-uniform in width and depth, and may be regular or irregular as totheir spacing and distribution on the exposed surface of the .material,and that such exposed surface may be either rough or even and may beproduced after the surface has been placed in position or may be made inthe form of blocks or sheets of predetermined sound-absorbing power,read i to be placed in position without any alteration. My inventionincludes all of these modifications, and such others as fall within thescope of the appended claims.

I claim as my invention:

-1. The method of modifying the acoustics of a room, auditorium or otherspace that comprises providing such a space with a boundary surfacehaving grooves communicating with said space, the Said grooves havingdefinite and predetermined soundabsorbing capacity per unit area of theexposed surface.

2. Sound-modifying material having grooves communicating with a normallyexposed surface of said material, said grooves being suflicientlnumerous to have substantial sound-modifying effect, and said surfacehaving definite-and predetermined sound-absorbing capacity per unit areaof said surface.

3. Material for forming an exposed surface of a room enclosure, the saidmaterial having a normally exposed surface provided with sound-absorbingopenings formed by the edges of laminations arranged side by side.

4. Material for forming anexposed surface of a room enclosure, the saidmaterial having a normally exposed surface pro vided withsound-absorbing openings formed by the edges of laminations arrangedside by side, and a backing member openings I 1o prisi formed b .theedges of laminations arranged si e, by side, a backing member se-- Jcured to said laminations, and means for spacing said laminations fromone an- 6 other, said spacin means consisting of bodies which indiviually have high soundabsorbing power.

7. Material for forming an exposedsurface of a room enclosure, saidmaterial coma backing member and laminations of sti ened fibrousmaterial arranged side by side and secured to said backing memr. v

8. A room enclosure having an exposed sound-absorbing wall composed ofmaterial 5 comprising a'backingmember. and lamina- 20 tions of thinmaterial arranged side by side and secured to'said backing member.

In testimony whereof I, the said JACOB MAZER, have hereunto set my hand.

JACOB MAZER.

